Field of the Invention
The present invention relates to a heat spreading module that is used in a portable electronic device such as a multi-function portable telephone (a smartphone) or a tablet type personal computer.
Description of Related Art
In a portable electronic device into which heat generation components such as an arithmetic element and an integrated circuit are built in a highly dense manner, a heat spot in which a temperature increases locally occurs, and the temperature becomes a cause of limiting arithmetic operation speed, a cause of reducing durability, or the like. Furthermore, in the portable electronic device, thickness reduction, weight reduction, and miniaturization are required in order to achieve satisfactory portability.
Various means for heat releasing and cooling in the portable electronic device have been proposed in the related art. For example, an information terminal, in which, for heat spreading, a fine heat pipe that is arranged between a circuit board and a battery pack transports heat of electronic components, such as a CPU, to a metal plate that constitutes a rear surface of a case or a rear surface of a display, is disclosed in Japanese Unexamined Patent Application, First Publication No. 2014-139501.
Wish a configuration that is disclosed in Japanese Unexamined Patent Application, First Publication No. 2014-13501, heat transportation by the fine heat pipe over a wide range of the metal plate dissipates heat of a heat generation body widely and suppresses a temperature of the heat generation body from increasing. Space that can be allowed for the fine heat pipe which performs heat transportation is extremely limited. Particularly in recent years, it has been required that the size of the fine heat pipe should be equal to or less than 0.5 mm or that the fine heat pipe should be thinned down to the extent of less than 0.5 mm.
In the fine heat pipe described above, because heat transportation capability is limited, the fine heat pipe cannot transport the heat to the entire metal plate. Therefore, with thermal conductivity by the metal plate, the heat has to be carried to a place that is a great distance away from the electronic component, and it is difficult to widely dissipate the heat that occurs in the electronic component and thus to lower the heat of the heat spot.